1. Technical Field
The present invention relates to a resonator element, a resonator, a physical quantity sensor such as an angular velocity sensor, and an electronic apparatus.
2. Related Art
Angular velocity sensors that detect rotational angular velocities are widely employed for navigation systems, attitude control systems of various kinds of apparatuses, image stabilizers of video cameras and digital cameras, etc. In the electronic apparatus, resonator element sensors that can be made compact are heavily used.
In related art, as an angular velocity sensor of a resonator element, a resonator including a vibration unit driven for driving and a vibrating and detection unit to detect detection vibration generated by rotation, the resonator detecting an angular velocity of a Z-axis rotational system in which plural vibration systems are formed to extend within a predetermined plane intersecting with the rotational axis Z is known (see Patent Document 1 (JP-A-11-281372)).
However, the angular velocity sensor of Patent Document 1 is a sensor that can detect vibration components of the vertical rotational axis, that is, the Z-axis rotational system, and it is necessary to mount the sensor vertically for the apparatus requiring plural detection axes and the sensor becomes larger as a sensor device.
Accordingly, as an angular velocity sensor that detects a rotational axis in parallel to the resonator surface, an angular velocity sensor that detects an angular velocity by allowing a detection unit continuously provided to a drive unit that drives in a torsional vibration mode around a torsion center axis intersecting with the rotational axis to perform torsionally rotational vibration and detect lateral flexural vibration of the detection unit generated by Coriolis force due to the rotational movement is known (see Patent Document 2 (JP-A-2007-212355)).
However, even by the above described angular velocity sensor according to Patent Document 2, detection accuracy may be reduced by generation of vibration leakage and output of signals not based on the angular velocity due to dimension accuracy of the resonator, so-called processing variations for vibrating detection arms provided at end parts in the Z direction by torsional vibration.